MIT and Cambridge police and firefighters coordinated the response to potential pipe bombs in New House early Tuesday morning. There was never any threat to campus safety, but the Cambridge bomb squad carried out a series of water-cannon “disruptions” on objects that looked like pipe bombs in a New House lounge, in an effort to disable them if they were dangerous.

The Cambridge Police Bomb Unit and MIT police responded early Tuesday morning to a report of “suspicious materials” — which looked similar to pipe bombs — in New House. Police evacuated New House and Next House, and cordoned off Amherst Alley near MacGregor. Six and a half hours later, MIT announced that the materials posed no threat to campus safety, and that the area was safe to re-enter.

At around 7:30 a.m. Tuesday, private contractors working on renovations reported “suspicious materials” in a common area on the third floor of New House 6 (German House). According to Cambridge Police spokesman Dan Riviello, contractors realized that they did not bring those materials into the building with them, so they called the police. The materials had the “appearance and characteristics of a pipe bomb,” according to a statement on MIT’s emergency information website.

By 2 p.m., investigators had concluded that the suspicious objects were actually a “collection of harmless materials.”

In an email to The Tech, Riviello said the concerning materials were “metal tubes, one solid, one containing ball bearings and a granular material.” The tubes were near a “group of liquids,” which were later found to be cleaning chemicals.

The tubes, said Riviello, “resembled materials that would be used in pipe bombs,” adding that pipe bombs often contain small objects, like ball bearings, that inflict more damage in an explosion.

New House is not occupied by students this summer, but nine people — GRTs who have apartments in the building — were evacuated when Cambridge police arrived on the scene at 7:40 a.m. Next House, which is also not currently occupied by undergraduates, was evacuated at around 11 a.m.

Before the harmless nature of the tubes had been ascertained, the atmosphere on West Campus was tense.

“It looked at first blush like it was pretty serious,” said John DiFava, MIT’s director of facilities operations and security.

Cambridge’s bomb squad and fire department used a high-pressure water cannon to “disrupt” the materials, in case they were dangerous. A water cannon can disable potential explosives without risking setting them off.

The first disruption occurred at around 9:50 a.m., a second at around 11:30 a.m., and a third at 12:40 p.m. Before the second disruption, media in the Westgate parking lot were asked to move further away from New House, to the lawn in front of Tang Hall, and Next House was evacuated. It took over an hour after the last disruption before the all-clear.

“MIT is grateful to the responding federal, state, and local agencies for investigating and ensuring the safety of the campus. The Institute also thanks the community for heeding requests to stay clear of the area while emergency officials did their work,” read a statement on the emergency website.

Both MIT police and the Cambridge Police Department led the response to the scare.

“It was a joint scene being handled by Cambridge and us,” DiFava said. The joint Cambridge-MIT crisis management system, he said, “works very well.”

In addition to the FBI, agents from the Bureau of Alcohol, Tobacco, Firearms and Explosives were present. Top MIT officials, including Chancellor W. Eric L. Grimson PhD ’80 and Vice President for Institute Affairs Kirk D. Kolenbrander, were also on-scene.

A hazardous materials decontamination tent was also set up in the Westgate parking lot, though it was not used.

During the heat of the crisis, rumors swirled among media and bystanders on the scene. Some outlets published unconfirmed reports that pipe bombs were discovered in New House; those reports were corrected throughout the course of the day. Bystanders told The Tech they had heard of a chemical spill inside the building, also incorrect.

The response by Cambridge and MIT police was a multi-person, multi-hour operation, but Riviello says there were “limited additional costs associated with the response” because CPD personnel were all regularly scheduled employees working the day shift during the scare. DiFava says MIT will not be billed for the operation’s costs.

Despite the power of the water cannon used to disrupt the tubes, DiFava said the incident area in New House sustained only “minor damage.” New House is currently undergoing renovations to install a new fire alarm and sprinkler system.

Also on Tuesday, police responded to and attempted to deactivate a device found near the Media Lab (E15), by the Ames St. crosswalk.

“That incident involved a GPS locator device with a wire and several small pieces of paper attached to it that was affixed to a bike rack on Ames Street,” said Riviello.

Upon further investigation, that object was also found to be harmless. CPD believes it may have been part of a geocaching game — where people hide objects and find others’ using GPS devices.

This is not the first time Cambridge’s bomb squad has visited campus. In April 2009, the bomb squad attempted to safely detonate a large, inert concrete block placed in Kresge Field by the Burton Third Bombers. The block — painted to look like a cartoon cherry bomb — was part of a hack to advertise the Bombers’ annual Dance Till You Drop party. In that incident, the bomb squad did not deploy a water cannon.

MIT’s emergency information website can be accessed at http://emergency.mit.net.